1. Field of the Invention
The present invention is generally related to the field of stem cell-based therapy and, more specifically, to compositions comprising stem cells and methods of preparing and using compositions comprising stem cells for the treatment and prevention of injury and disease.
2. Description of the Related Art
Due to their remarkable ability to regenerate and develop into a variety of cell types, stem cells possess great therapeutic potential in the treatment of a wide variety of diseases and injuries, particular those involving the destruction or damage of normal tissue, such as spinal cord injuries, Parkinson's Disease, Alzheimer's Disease, and multiple sclerosis. Until fairly recently, it was thought that multipotent stem cells could only be isolated from embryonic tissue. However, it has now been discovered that multipotent stem cells exist in a variety of adult tissues, including bone marrow, skin, brain, muscle and adipose tissue. This discovery has sparked increased interest in stem cell-based therapies, since such adult stem cells are more readily available than embryonic stem cells, and their use does not raise the same ethical concerns.
One significant limitation to the therapeutic use of stem cells is that they are present in very low numbers in most adult tissues, and their isolation and purification is a tedious and expensive process. The generally practiced method of preparing stem cells before providing them to a patient involves purifying cells from a tissue sample, isolating stem cells, e.g., using antibodies specific to stem cell surface markers from other cells, and/or culturing the cells. In addition, many procedures further involve treating the cells with an agent that induces differentiation down a specific lineage. The reagents used for the purification, culturing and differentiation of stem cells are very expensive, thus limiting the availability of stem cell-based therapies. In addition, the procedures involved in preparing and storing stem cells can result in cell death and loss of function, thus reducing the number of useful stem cells isolated and limiting their ability to be stored and shipped prior to use.
Clearly, there is a need in the art for improved methods of preparing stem cell populations suitable for therapeutic and prophylactic use, including methods capable of purifying a high number of viable cells from a tissue sample, particularly for autologous uses, which may be performed with increased ease and reduced costs. In addition, there is a related need for methods of preparing purified stem cells from a patient's tissue sample obtained by a medical professional, and providing the purified cells to a medical professional for administration to the patient. The present invention meets these needs by providing novel methods of preparing stem cell populations, novel compositions comprising stem cells, and streamlined procedures for preparing and providing stem cells for delivery to a patient.